Admin Tools

#37514 Admin Tools Installation Fails

Posted in ‘Admin Tools for Joomla!’
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Environment Information

Joomla! version
PHP version
Admin Tools version


After attempting to install AdminTools on our dev server 3 times we get the same error on all admin screens "Class 'Joomla\Plugin\System\AdminTools\Extension\AdminTools' not found"

Akeeba Staff

When that happens delete the file administrator/cache/autoload_psr4.php and reload any page of your site. This file will be regenerated by Joomla.

This file is supposed to be removed and regenerated every time you install or upgrade an extension. Its purpose is to serve as an autoloader cache, telling Joomla which PHP namespace prefixes are found where on your site. This is how Joomla 4 loads extensions which don't use the Joomla 3 legacy compatibility layer (our extensions are native Joomla 4). If Joomla fails to regenerate that file you get class not found errors like the one you got.

Nicholas K. Dionysopoulos

Lead Developer and Director

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